In recent years, electronic devices have been introduced for controlling various electrical equipment in a vehicle such as an automobile. In an electric power steering apparatus as an example of an electrical equipment into which an electronic device is incorporated, there is provided a motor drive unit in an enclosure accommodating an electric motor for steering an automobile and the electronic device is mounted on the motor drive unit. The electronic device is incorporated as a power module into the motor drive unit.
The power module is constituted as a so-called semiconductor module on which a power element such as a field effect transistor (FET) or an insulated gate bipolar transistor (IGBT) suitable for controlling an electrical equipment driven with a relatively large current, such as an electric power steering apparatus. Such a type of power module is also called “in-vehicle module”, because it is mounted on a vehicle.
In the related art, there is, for example, a technique described in PTL 1 as this type of semiconductor module. In this technique, wires are used for electrical interconnections that joint wiring patterns and bare-chip transistors on a metal substrate.
Additionally, for example, as in a technique described in PTL 2, lead components are used for electrical connection of semiconductor elements mounted on a metal substrate to perform solder mounting. Here, the semiconductor elements and the substrate having different heights respectively, are jointed by inclining the lead components.
Moreover, for example, as in a technique described in PTL 3, in order to reduce the stress in a connector wiring, a rising bending portion may be provided, or a fuse shape (a wavy shape) may be provided in the middle of the wiring.